Criptografia de sinais ópticos por embaralhamento e codificação espectral de atraso e fase

• Autor(a) principal: Friedrich, Philipp Farnetani
• Data de Publicação: 2020
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/214074
• topic: Comunicações ópticas; Criptografia; Segurança de sistemas

The intense increase in network traffic observed since the 1990s has stimulated the development of technologies to expand the data transmission capacity on the Internet. At the same time that this evolution popularized the use of computers and other digital communications devices, problems related to network security arose. Much of these problems are solved by using data encryption. However, the signals that travel through the network links are subject to espionage and also need to be protected. To accomplish this task, the use of signal encryption has been considered. In particular, transparent optical networks are attractive for this purpose because they transmit signals from source to destination without having to process them. Therefore, for switching nodes of this type of network, it does not matter whether the signals are encrypted or not. In addition, optical communications are responsible for transmitting most of the data that passes through the core of the telecommunications network. In this work, an optical encryption technique is presented, in which two distinct optical signals are submitted to three stages of encryption. In the first, two or more signals are divided into several spectral slices and the slices of these signals are shuffled together. In the second stage, each slice receives a phase shift. In the last stage, the slices are subjected to delay of the symbol period order. This technique is evaluated through simulations in the VPI Transmission Maker ™ Optical Systems (VPI) software for signals modulated by quadrature phase shift keying (QPSK) of 56 Gb/s. The results suggest that the bit error ratio (BER) of the encrypted signal is approximately 0.5, making espionage difficult. On the other hand, the decrypted signals can be recovered with a penalty of 4 dB. In terms of security, it is estimated that 2,164 ∙ 10��������������� attempts are required to ensure the success of brute force attacks.